The invention concerns a method for producing fluoroalkyl-functionalized hybrid polymer coatings with low surface energy and low tendency to become soiled.
Functional hybrid polymer coatings are becoming increasingly important in fields of application in which properties of scratch resistance, abrasion resistance and chemical resistance or even UV absorption are required. Coatings of this kind are also increasingly being used in corrosion protection and in thermal insulation.
Important criteria for the quality of such coatings are a low surface energy and low tendency toward soiling. The use of such coatings is possible for many substrates. These include plastics, metals, glasses, ceramics and wood, as well as other nonmetallic inorganic or organic substrates.
Among these coatings, fluoroalkyl-functionalized silanes, which enable permanent protection of a surface against soilings of any kind, stand out in particular.
According to the prior art, highly scratch-resistant and highly wear-resistant coatings are known from DE 38 28 098. However, these coatings have the disadvantage that the optical properties of the surfaces often do not satisfy the high demands on such coatings, because optical deficiencies form (so called fish eyes).
DE 198 40 009 describes the production of UV-hardening sols, that can be applied very readily by flow coating andxe2x80x94for nonmetallic substratesxe2x80x94even by immersion, but spray application (important for geometrically complex objects), and immersion of metal substrates are not possible in this case, since the sols turn to gels very rapidly through contact with metals.
DE 41 18 184 describes a coating composition based on fluorine-containing inorganic polycondensates. In the process of producing these coatings described there the addition of the fluorinated starting compounds is a very critical point in process. Here the addition can take place only at a precisely defined point in time, between a precondensation step and the end condensation step, so that the condensation process has to be interrupted and because of this the process becomes more costly.
For this reason the invention is based on the task of developing a method for producing low soiling coatings that remedies the disadvantages of the prior art.